1. Field of the Invention
The present invention relates to an ink jet recording head, and a method for manufacturing the ink jet recording head.
2. Description of the Related Art
A mold (male type) for an ink channel (path) is formed on a substrate by using a resin having solubility. Thereafter, the mold is coated with a covering resin to form an ink discharge surface (an orifice plate). At this state, a surface of the covering resin rises in a convex shape on the male mold for the ink channel due to surface tension and the like. That is, the surface of the covering resin does not become flat. This non-flat surface of the covering resin is not desired when forming of an ink discharging hole. Therefore, conventionally, as a method for manufacturing an ink jet recording head, technique mentioned below was proposed.
A pattern for forming an ink channel and also a pattern serving as a base are formed from a resin layer having solubility on a substrate. As a result, when a covering resin is coated on those patterns, the covering layer, which will becomes an orifice plate, on the resin layer having solubility, is made to be flat by the base (for example, see Japanese Patent Application Laid-Open (JP-A) No. 10-157150, FIG. 1).
That is, as shown in FIG. 11, when a pattern for forming an ink channel 210 is formed from a resin layer having solubility (not shown in the drawings) on a substrate 200 on which heating resistors 202 are formed, a base is also formed in the vicinity of the ink channel 210 (the pattern for forming an ink channel 210) from the resin layer having solubility (not shown in the drawings) on the substrate 200. As a result, the resin layer 204, which will become an ink discharging surface, on the resin layer having solubility can be flatly formed. Next, ink discharge openings 206 are formed on the resin layer 204. Together with this, the resin layer 204 on the base is removed. Thereafter, an ink supplying opening 208 is formed on the substrate 200. Then, the resin layer serving as the pattern for forming the ink channel 210 and also the resin layer serving as the base are solved out (eluted), and a hole 212 is formed.
Or, in addition to the technique mentioned above, it is proposed that a penetration opening provided on a covering resin layer is formed so as to have a dimension which is sufficiently larger than that of the base in order to remove the resin, having solubility, serving as the base (for example, see Japanese Patent Application Laid-Open (JP-A) No. 11-138817, FIG. 1).
In those technique mentioned above, the base is formed form the resin having solubility which is the same resin of the pattern for forming the ink channel 210. Accordingly, it is necessary to remove this resin having solubility (the base) because there is a risk of cracking due to difference between coefficients of thermal expansions of this resin having solubility and the covering resin layer 204.
However, in those technique mentioned above, because a region which in not covered by the resin (the hole 212) is formed on a surface of the manufacturing-completed ink head, a region between the substrate 200 and the resin layer 204 is eroded by an ink splashed from the ink discharge hole 206, as a result, adhesion of the resin layer 204 deteriorates. Or, the ink pools at the region. These cause dust.